The plots of Rt over time show a clear downward trend since early-November, with estimates of Rt lower in all regions in comparison to last week. These lower values of Rt are likely to be the combined result of various social distancing interventions, detected through the Google mobility data, and half-term school closures.
The number of new infections is decreasing in both the North East and Yorkshire, and the North West, but continuing to increase in the South East. In all other regions, incidence has plateaued.
We believe that the number of deaths occurring each day has already reached a peak in most regions. However, the number of deaths reported publicly each day may continue to increase for some weeks; these reports are based on deaths identified during the previous 24-hours and also include a number of delayed reports of deaths that had occurred over previous days (for more information see nowcasting COVID-19 deaths).
The lock-down introduced on the 5th of November will have induced changes in contact patterns, which cannot be quantified with any certainty at this point, but have the potential to induce a continued decrease in the Rt values and the number of new infections. Further changes will be reflected in the weekly iterations of our model.
Real-time tracking of an epidemic, as data accumulate over time, is an essential component of a public health response to a new outbreak. A team of statistical modellers at the MRC Biostatistics Unit (BSU), University of Cambridge, are working to provide regular now-casts and forecasts of COVID-19 infections and deaths. This information feeds directly to the SAGE sub-group, Scientific Pandemic Influenza sub-group on Modelling (SPI-M), and to regional Public Health England (PHE) teams.
We fit a transmission model (Birrell et al. 2020) to a number of data sources (see ‘Data Sources’), to reconstruct the number of new COVID-19 infections over time in different age groups and NHS regions, estimate a measure of ongoing transmission and predict the number of new COVID-19 deaths.
We use:
Data are stratified into eight age groups: <1, 1-4, 5-14, 15-24, 25-44, 45-64, 65-74, 75+, and the NHS England regions (North East and Yorkshire, North West, Midlands, East of England, London, South East, South West).
Value of \(R_t\), the average number of secondary infections due to a typical infection today.
The percentage of a given group that has been infected.
NB: negative growth rates are rates of decline. Values are daily changes.
| Region | Median | 95% CrI (lower) | 95% CrI (upper) |
|---|---|---|---|
| England | -0.01 | -0.02 | 0.01 |
| East of England | -0.02 | -0.06 | 0.02 |
| London | 0.00 | -0.03 | 0.03 |
| Midlands | 0.00 | -0.03 | 0.02 |
| North East and Yorkshire | -0.03 | -0.05 | -0.01 |
| North West | -0.06 | -0.08 | -0.03 |
| South East | 0.01 | -0.02 | 0.05 |
| South West | 0.00 | -0.04 | 0.03 |
Halving times in days, if a region shows growth than value will be NA.
| Region | Median | 95% CrI (lower) | 95% CrI (upper) |
|---|---|---|---|
| England | 106.20 | 34.16 | NA |
| East of England | 38.52 | 11.87 | NA |
| London | NA | 21.48 | NA |
| Midlands | 586.11 | 26.24 | NA |
| North East and Yorkshire | 21.80 | 12.72 | 64.78 |
| North West | 11.77 | 8.25 | 19.79 |
| South East | NA | 41.37 | NA |
| South West | 613.54 | 18.71 | NA |
Doubling times in days, if a region shows decline then the value will be NA.
| Region | Median | 95% CrI (lower) | 95% CrI (upper) |
|---|---|---|---|
| England | NA | 86.90 | NA |
| East of England | NA | 39.61 | NA |
| London | 551.04 | 21.35 | NA |
| Midlands | NA | 37.93 | NA |
| North East and Yorkshire | NA | NA | NA |
| North West | NA | NA | NA |
| South East | 46.27 | 14.83 | NA |
| South West | NA | 20.00 | NA |
NB: negative growth rates are rates of decline. Values are daily changes.
| Region | Median | 95% CrI (lower) | 95% CrI (upper) |
|---|---|---|---|
| England | -0.02 | -0.02 | -0.01 |
| East of England | -0.02 | -0.04 | 0.00 |
| London | -0.01 | -0.03 | 0.02 |
| Midlands | -0.01 | -0.02 | 0.00 |
| North East and Yorkshire | -0.02 | -0.03 | -0.01 |
| North West | -0.04 | -0.05 | -0.02 |
| South East | 0.00 | -0.01 | 0.03 |
| South West | 0.00 | -0.02 | 0.02 |
Halving times in days, if a region shows growth than value will be NA.
| Region | Median | 95% CrI (lower) | 95% CrI (upper) |
|---|---|---|---|
| England | 41.87 | 30.61 | 72.12 |
| East of England | 32.17 | 17.28 | 697.35 |
| London | 119.58 | 24.83 | NA |
| Midlands | 62.46 | 27.48 | NA |
| North East and Yorkshire | 35.32 | 21.94 | 91.89 |
| North West | 18.95 | 14.49 | 28.63 |
| South East | NA | 46.41 | NA |
| South West | 207.37 | 27.90 | NA |
Doubling times in days, if a region shows decline then the value will be NA.
| Region | Median | 95% CrI (lower) | 95% CrI (upper) |
|---|---|---|---|
| England | NA | NA | NA |
| East of England | NA | NA | NA |
| London | NA | 36.49 | NA |
| Midlands | NA | 234.08 | NA |
| North East and Yorkshire | NA | NA | NA |
| North West | NA | NA | NA |
| South East | 142.67 | 25.75 | NA |
| South West | NA | 35.17 | NA |
The blue lines is show when interventions have been introduced (lockdown on 23 Mar and the relaxation of measures on 11 May), and the red line shows the date these results were produced (22 Nov).
The figure below shows the probability that \(R_t\) is greater than 1 (ie: the number of infections is growing) in each region over time. Clicking the regions in the legend allows lines to be added or removed from the figure.
Copyright © MRC Biostatistics Unit, University of Cambridge